Polyamide-6-Based\nThermoplastic Elastomers and Their\nFilaments with Improved Thermomechanical Performance Enabled by Enhanced\nHydrogen Bonding Interactions

Enhancing\nthe glass transition temperature of the hard\nphase (<i>T</i><sub>g‑HS</sub>) and the tensile strength\nof PA6-based\nthermoplastic elastomers (TPAEs) has been a long-standing challenge,\nsignificantly restricting their application in textiles. In this study,\nthis issue was effectively addressed by incorporating <i>p</i>-phenylenediamine (PPD) into the molecular chains, which induces\nenhanced hydrogen bonding interactions in TPAEs. Consequently, the\nprepared PPD-modified TPAEs (PPD-TPAEs) demonstrated a well-defined\nnanophase-separated morphology and a <i>T</i><sub>g‑HS</sub> of 48.2 °C, which is more than 5 °C higher than that of\nTPAEs with the same soft segment weight concentrations (<i>C</i><sub>SS</sub>). Additionally, the <i>T</i><sub>g‑HS</sub> increased with higher <i>C</i><sub>SS</sub> values due\nto the augmented hydrogen bonding interactions in PPD-TPAEs. The tensile\nstrength and elongation at break of PPD-TPAEs were over 1.9 and 2.6\ntimes greater, respectively, than those of TPAEs with the same <i>C</i><sub>SS</sub> value. Notably, filaments produced from molten\nPPD-TPAEs with 44% soft segments (PPD-TPAE-40) exhibited thermomechanical\nperformance comparable to Spandex, underscoring their potential application\nin the textile industry.